Zac Williams celebrates the Giants' round nine win over Gold Coast at Metricon Stadium in August. Picture: Getty Images

CARLTON has emerged as a leading contender for star Greater Western Sydney free agent Zac Williams.

AFL.com.au understands the Blues will look to prioritise the addition of speed to an improving young list during the Trade Period and have identified Williams as one of their top targets.

Williams, who is uncontracted beyond season 2020 and subsequently remains one of the competition's most sought-after restricted free agents, is yet to sign the offer of a multi-year extension that has been tabled by the Giants.

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The 25-year-old, who is understood to have also attracted the interest of Essendon and North Melbourne and remains a priority re-signing for his current club Greater Western Sydney, is undecided on his future after 109 games over eight seasons in New South Wales.

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However, rival clubs believe Carlton is among the frontrunners to secure his signature should he decide to leave Greater Western Sydney at the conclusion of the campaign.

As a restricted free agent, the Giants would have the option of matching any offer potentially put forward by the Blues in a move that would force trade talks between the two clubs.

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Should they not do so, Carlton – or any side – could potentially secure Williams in a deal that would cost the club no draft capital in a trade.

A deal for Williams would make the running defender the fifth ex-Giant on the books at Ikon Park, potentially joining former teammates Matt Kennedy, Will Setterfield, Lachie Plowman and Caleb Marchbank in making the switch between the two clubs.

Williams, a dashing half-back, averaged 23.7 disposals per game last season and made a successful midfield switch during a thrilling preliminary final victory over Collingwood to spearhead Greater Western Sydney's journey to the Grand Final.

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A hamstring complaint this season has restricted the lightning and versatile Williams to just seven of a possible 12 games, but he has still proved one of the side's most important players with his line-breaking speed since returning to the backline this year.

Carlton is also expected to again renew its interest in star Sydney forward Tom Papley at season's end, though the club remains tight-lipped about the prospect of a further push for the small forward.

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Papley requested a trade to the Blues last October, though the club was unable to negotiate a deal with the Swans after an offer including pick No.9 was rejected on multiple occasions in a protracted saga.

The push for Williams and Papley is expected to kickstart an aggressive pursuit of ready-made talent at Ikon Park, with the club hopeful of fast-tracking its rise up the ladder by adding to prior off-season recruits including Jack Martin, Eddie Betts and Mitch McGovern.